Existing isopentyl acetate (IPA) vapor spray bars used to dry semiconductor substrates using the Marangoni effect are subject to clogging. A clogged vapor spray bar results in streaking on the substrate and thus, the knife becomes unusable. Typically, such vapor spray bars are formed using a tube with a line of very small spray orifices arranged along the length of the tube. The small-sized spray orifices are desirable to reduce the amount of IPA vapor that is used in drying but make the vapor spray bar more prone to becoming clogged. The tube is welded to the IPA supply channel during manufacturing and once welded, the tube becomes unserviceable. Thus, if an orifice becomes clogged, the vapor spray bar is typically disposed and replaced with a new vapor spray bar. Therefore, what is needed are methods and apparatus that enable a vapor knife suitable for use in Marangoni drying to be repaired and/or cleaned.